Office chairs include a seat-back arrangement having a horizontally enlarged seat and a back projecting upwardly from a rear edge of the seat. The seat has a front edge thereof which defines the forwardmost point of contact between the upward facing seat surface and the thighs of a chair occupant or user. Various chairs have been designed which allow for adjustment of the contact points between the chair seat and the occupant's thighs.
The invention relates to an improved chair seat arrangement which allows adjustment of the contact point. In the inventive seat arrangement, the seat includes a front portion thereof which is adapted to support the thighs of the user and also is deflectable downwardly in response to the weight of the occupant and the occupant's movements. The seat is formed of a resilient material which is normally biased to an undeflected position.
To adjust the contact point between the front seat section and the occupant's thighs, an adjustment mechanism is provided so that the front seat portion may be pulled downwardly or pushed upwardly depending upon the seat construction, which adjusts the forwardmost contact point between the front seat section and the occupant's thighs and thereby adjusts the effective length of the seat. The adjustment mechanism preferably provides an adjustment force acting opposite to the resilient restoring force of the seat while the seat section remains essentially unrestrained in the downward direction. Thus, when the adjustment mechanism modifies the deflection of the front seat section to an adjusted position, the front seat section is still able to move downwardly away from the adjusted position in response to the weight and movements of the occupant, or upon removal of the occupant's influences, to restore itself to the adjusted position defined by the adjustment mechanism.
In one embodiment, the adjustment mechanism comprises a cable which is connected to the front seat section wherein pulling on the cable pulls the front seat section downwardly, but the flexibility of the cable still allows for additional downward deflection away from the adjusted position. In another embodiment, the adjustment mechanism may comprise a resilient lever which pushes the seat upwardly but is deflectable downwardly.
Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the system and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.